Investigating Mechanoreceptors in Rodent Skin
Laura Medlock, Dhekra Al-Basha, Adel Halawa, Christopher Dedek, Stephanie Ratte, and Steven Prescott
(see article e1252242024)
Scientists have advanced our understanding of somatosensory coding by investigating the whisker system in rodents. But somatosensory coding in humans and nonhuman primates has been explored mostly in nonhairy (glabrous) skin, which likely operates differently than whiskers. Whether somatosensory coding in rodent skin bears similarity to that of nonhuman primates is a critical knowledge gap that Medlock and colleagues explored by investigating mechanoreception in the skin of rodent hindpaws. The authors used electrophysiology to record from skin nerve fibers as rats and mice responded to stimuli. Next, using results from intricate data analyses, they simulated these nerve fibers to explore intrinsic mechanisms explaining response differences to stimuli. While mechanoreceptors in other species typically exhibit a preference for low- or high-frequency stimuli, resulting in a bimodal distribution, Medlock et al. observed a continuum of frequency preference in rodent mechanoreceptors. This suggests that their heterogeneity is greater than in other species. This difference may be important for somatosensory researchers using different mammalian systems.
This sagittal section of a Penk-tdTomato mouse tongue shows tdTomato-positive taste arbors (magenta) innervating taste buds expressing keratin-8 (green). See Ohman et al. for more information.
A Taste Neuron Subpopulation for Aversive Tastes
Lisa Ohman, Tao Huang, Victoria Unwin, Aditi Singh, Brittany Walters, et al.
(see article e0583242024)
Taste neurons in the peripheral nervous system are highly diverse on morphological, genetic, and functional levels. Ohman and colleagues investigated the relationship between all these components in their study. They related taste bud innervation patterns to the functioning of a subset of taste neurons expressing proenkephalin (Penk+) in male and female mice. Consistent with their innervation patterns to multiple taste bud cell types, Penk+ neurons were more responsive than other taste neurons to aversive tastes (sour, bitter, or high in salt). This suggests that Penk+ neurons are selective to negative taste qualities. However, the complex and diverse morphology of taste arbors—the part of the axon that is in each taste bud—appeared unrelated to taste neuron subtype. This demonstrates that taste neuron axon terminal morphology may be driven by plasticity and not genetics. These findings provide some clarity on the interplay between morphological, genetic, and functional attributes of taste neurons.
Footnotes
This Week in The Journal was written by Paige McKeon
